def export_path(path):
doc = ezdxf.new()
msp = doc.modelspace()
bbox = BoundingBox(path)
msp.add_polyline3d(path, dxfattribs={"layer": "Path", "color": 2})
for curve in cubic_bezier_interpolation(path):
msp.add_polyline3d(curve.approximate(20),
dxfattribs={
"layer": "Bézier",
"color": 1
})
doc.set_modelspace_vport(center=bbox.center, height=bbox.size[1])
doc.saveas(DIR / "path1.dxf")
def test_vertex_interpolation():
points = [(0, 0), (3, 1), (5, 3), (0, 8)]
result = list(cubic_bezier_interpolation(points))
assert len(result) == 3
c1, c2, c3 = result
p = c1.control_points
assert p[0].isclose((0, 0))
assert p[1].isclose((0.9333333333333331, 0.3111111111111111))
assert p[2].isclose((1.8666666666666663, 0.6222222222222222))
assert p[3].isclose((3, 1))
p = c2.control_points
assert p[0].isclose((3, 1))
assert p[1].isclose((4.133333333333334, 1.3777777777777778))
assert p[2].isclose((5.466666666666667, 1.822222222222222))
assert p[3].isclose((5, 3))
p = c3.control_points
assert p[0].isclose((5, 3))
assert p[1].isclose((4.533333333333333, 4.177777777777778))
assert p[2].isclose((2.2666666666666666, 6.088888888888889))
assert p[3].isclose((0, 8))
#
# http://help.autodesk.com/view/OARX/2018/ENU/?guid=OREF-AcDbSpline__setFitData_AcGePoint3dArray__AcGeVector3d__AcGeVector3d__AcGe__KnotParameterization_int_double
# Remark in the AutoCAD ObjectARX reference for AcDbSpline about construction
# of a B-spline from fit points:
# degree has no effect. A spline with degree=3 is always constructed when
# interpolating a series of fit points.
# Sadly this works only for short simple splines.
doc, msp = setup()
msp.add_spline(points,
degree=2,
dxfattribs={
'layer': 'BricsCAD B-spline',
'color': 2
})
bezier_curves = cubic_bezier_interpolation(points)
s = bezier_to_bspline(bezier_curves)
msp.add_spline(dxfattribs={
'color': 6,
'layer': 'Cubic Bezier Curve Interpolation'
}).apply_construction_tool(s)
zoom.extents(msp)
doc.saveas(DIR / 'concept-4-cubic-bezier-curves.dxf')
# ----------------------------------------------------------------------------
# A better way to create a SPLINE defined by control vertices from fit points
# without given end tangents for SHORT B-splines:
# ----------------------------------------------------------------------------
doc, msp = setup()
def profile_bezier_interpolation(count, path):
for _ in range(count):
curves = list(cubic_bezier_interpolation(path))